In the past, electronic as well as mechanical postage printing devices featured rotatable printing drums with settable printing wheels for printing postal values.
More recently, with the advent of automated postage stations, thermal printers have replaced the previous fixed dies for printing postage. The thermal printing mechanisms are uniquely adaptable for use within these automated postage stations, in that they are capable of printing indicia, slogans, postal values, and other postage information in a facile manner. These thermal printing mechanisms are easily controlled by a microprocessor that initiates voltage pulses for heating the thermal printing elements to rapidly provide a postage stamp.
While the thermal printers are relatively fast as compared with the previous mechanical drum printers however, they are relatively slow when printing indicia, such as an eagle stamp, when considering the speed of the microprocessor signals.
This problem results from the large amount of electronic control required to print the eagle indicia upon the stamp.
It has been discovered that the thermal printing of postage can be further speeded by dichotomizing the printing of the postal information in a fixed and variable format.
The variable postage data such as postal value and date is easily iniltiated through electronic input to a thermal head printer as previously accomplished.
However, this invention now contemplates the thermal printing of indicia such as the eagle stamp, postage meter identification number and optional slogan, as fixed information. This fixed information is now thermally printed separately from the variable, electronically controlled data by another thermal printer having a fixed unalterable thermal printing screen carried by a rotatable drum.
The two separate thermal printings form a composite of the final complete postage stamp by maintaining proper sequential registration between fixed and variable printings.
The above bifurcated arrangement not only provides for a speedier thermal printing of postage, but also has the further advantage of providing better postage meter security. This is accomplished by the fact that the meter number and eagle indicia have a unique design and are additionally in place within the system. Such indicia cannot be easily altered or modified within the course of normal postage meter operation.